1. Field of the Invention
This invention relates to compositions for diagnosis of dental caries activity, more particularly to compositions capable of evaluating instantly the status praesens of dental caries (decayed tooth) and its activity by having recourse to dental plaque collected from the dental caries patient's oral cavity. According to this invention, it is possible above all to evaluate instantly the status praesens of the patient's dental caries and its activity by means of color reaction like Schneider's test without any cultivation of cariogenic bacteria being required.
2. Description of the Prior Art
It is said that three important factors, e.g. cariogenic bacteria, sugar and dentine, participate in genesis and development of dental caries (Ind. Dent. J., 12, 443 (1962)). In consequence, a synthetic judgement as to all of these factors should be brought about in order to have the full knowledge of the genesis and development of dental caries, but it is difficult to make simultaneous measurements of all these factors. Under the circumstances, different test methods have been inquired into whereby the status praesens of dental caries can be objectively evaluated by observing the condition of cariogenic bacteria in dental plaque for reason that this condition is highly correlated with dental caries. Snyder's test, salivary lactobacillus count test, dental enamel dissolution test, salivary acid fermentation test, salivary buffering power test, etc. are the typical ones among them. However, these test methods have offered some problems in that troublesome operations are involved in spite of the results to be obtained being not consistent, that the instruments to be used are complicated and moreover that it takes a long time for cultivation of cariogenic bacteria. With the use of these methods, therefore, examination of the oral cavity still remains indispensable for judging of the status praesens of dental caries.
The authors of this invention, having taken the situation as stated above into account, have pursued their researches with a view to developing any method for evaluating the status praesens of dental caries that could take the place of examination of the oral cavity, and have previously proposed a method for test of dental caries activity (Public Disclosure of Patent Application No. 1589/75). This method consists in placing dental plaque collected from the oral cavity in an aqueous solution containing a carbon source (saccharose), a nitrogen source (Tryptose (an amino acid composite prepared by Difco in U.S.A.), etc.) and coloring agents as well as an agent inhibiting proliferation of sundry germs not related with dental caries and then, after cultivation of the bacteria for a given duration, in deciding on dental caries activity on the basis of coloration of the culture solution. Though this method is certinaly an excellent one in matter of simplicity of operation and accuracy in evaluation, yet it is a method which essentially requires bacterial cultivation and therefore certain time until any judgement has been given.